1. Field of the Invention
This invention relates to a squeezable container that forces the liquid to be dispensed toward the top of the container. The container also reduces or eliminates the likelihood of exposure of the liquid in the container to air.
2. Related Art
Most squeeze bottles necessarily allow air into the bottle as the liquid is dispensed out of the bottle. This exposes the liquid to contamination. When exposed to air, some liquids can cure (glue, for example), causing the nozzle of the container to become clogged. Also, whether because of contamination or curing, the shelf life of the liquid is reduced by the entry of air to mix with it. One additional problem is that once the bottle is set upon its base, the liquid falls to the bottom of the bottle. With some thick liquids, this means that the bottle must be shaken to get the liquid to the nozzle before the liquid is dispensed again. Lastly, the liquid clinging to the sides of the bottle is unsightly. For this reason, most squeeze bottles are made of some sort of opaque plastic.
U.S. Pat. No. 4,239,132 uses two one-way valves and an air bladder to try to force the liquid out of the bottle. This design creates two airtight chambers within the bottle. The problem with this design is that liquid can be trapped far away from the nozzle. The liquid becomes trapped because there is no control over how the air bladder inflates. The air bladder will often inflate in a way that traps some of the liquid far away from the nozzle. Then the trapped liquid can no longer be dispensed.
U.S. Pat. No. 4,760,937 is similar to the previous cited patent. The patent discloses a configuration that employs two one-way valves and also divides the interior of the bottle into two chambers. The difference is that U.S. Pat. No. 4,760,937 puts the liquid into a bag. The air entering the rear chamber still displaces the liquid. The problem with this design is that there is no control over the way in which the bag containing the liquid will compress. Often the bag will compress in a way that blocks the nozzle and then prohibits all of the liquid from being dispensed.
U.S. Pat. Nos. 5,687,882 and 6,364,163 are similar to U.S. Pat. No. 4,239,132 in that they disclose configurations that employ one-way valves and an air bladder to displace the liquid. They are different in that they both employ a column attached to a sliding collar (sometimes with a piston) in order to try to control the deployment of the air bladder. Both of these inventions also divide the interior of the bottle into two chambers. There are a few problems with these inventions. The first problem is that when the bottle is squeezed the bladder will not neatly deploy as envisioned. Sometimes, a bubble of liquid will force itself behind the piston or collar; this bubble of liquid will end up being trapped remote from the nozzle. The bubbling and trapping issue seen in all prior inventions is intrinsic to any design where the interior of the bottle is divided topologically into only two chambers. In any two-chambered design there arises a contradiction: if the plunger is made too tight, then too much force is required to move it; and, if the plunger is made too loose (or if the plunger is flexible, or if there is no plunger) then some liquid will bubble through to the other side during operation. An additional problem with U.S. Pat. Nos. 5,687,882 and 6,364,163 are their complexity: the costs of producing these bottles and packaging liquid in them are prohibitive.